The invention concerns dual drive wheels for an agricultural harvester and, particularly, a wheel arrangement for straddling a row of the crop to be harvested and also a method of installing the wheels on the harvester.
"Straddle duals" are gaining favor in harvesting operations and particularly in the combining of row crops. The use of widespaced dual wheels straddling a crop row avoids mashing down the crop residue in the row, reducing the likelihood of tire damage from the stubble, and enhances the stability and traction of the harvester. If duals are used, relatively narrower width tires can be used, running easily in the space between the rows.
When the crop is planted on ridges, use of straddle duals preserves the ridges during harvesting and avoids soil compaction in the rows and possible consequent yield reduction. All of the crop residue is left in condition for salvaging or harvesting if desired.
The harvester stability provided by straddle duals, with tires running on the relatively clear level ground between the rows, helps in control of front-end equipment so that, for example, wide grain heads can safely be run closer to the ground.
Existing straddle dual wheel arrangements for combine harvesters are, typically, adaptations of dual wheel designs already available for agricultural tractors and combines. They have simply been modified to provide the greater spacing between each pair of duals required to straddle the crop row with adequate clearance. Typically, a generally cylindrical spacing element is used in connecting and spacing the side-by-side wheels. While this form of connection is generally acceptable for closely spaced conventional duals in tractors or combines, the increased loading of the connecting means resulting from wider spacing of the wheels makes this method less efficient and attractive. In addition, when the so-called band configuration is used, mud build-up between the wheels soon becomes a problem.
Also known are conventional dual wheel arrangements consisting of pairs of identical dished wheels, assembled with their offset centers abutting each other. If the offset is great enough no spacers are needed between the wheels. However, in these cases, the configuration is used only for convenience in making a dual (side-by-side) wheel installation and not for establishing a predetermined wheel tread or lateral spacing. And in the resulting assembly the members of the dual wheel set are closely spaced so as to minimize transport width.
Combine harvester drive wheels and tires are typically large and heavy and awkward to maneuver. Known dual wheel designs are not inherently safe and convenient to mount.